Asteroids

2021TN9 help

Last update: 2025-09-10 00:30 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.975

Aphelion (Q)

2.108

Eccentricity (e)

0.368

Inclination (i)

10.4

deg

Orbit period (P)

699.1

Earth MOID

0.02169

U parameter

8.0

Next Earth close approach

Date

2065-11-07

Nominal distance (from Earth center)

0.10693

15996498

Maximum Brightness

25.2

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

26.8

mag

Diameter

12 - 26*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-10-09

Observatory

Mt. Lemmon Survey

ORBIT VISUALISATION TOOLS

External links

Proper elements

Epoch

Near present day

Near middle of observation arc

Orbit properties

Epoch
Semimajor Axis
Eccentricity (e)
Inclination (i)
Long. of Ascending Node (Ω)
Arg. of Perihelion (ω)
Mean Anomaly (M)
Perihelion distance
Aphelion distance
Asc. Node-Earth Sep.
Desc. Node-Earth Sep.
MOID
Orbit Period
U parameter

Value

1-sigma variation

Unit

Epoch

Value

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.541517

1-sigma variation

0.001583

Unit

Eccentricity (e)

Value

0.367505

1-sigma variation

0.000654

Unit

Inclination (i)

Value

10.3915

1-sigma variation

0.0140

Unit

Long. of Ascending Node (Ω)

Value

17.5436

1-sigma variation

0.0011

Unit

Arg. of Perihelion (ω)

Value

35.4579

1-sigma variation

0.0096

Unit

Mean Anomaly (M)

Value

38.02024

1-sigma variation

1.16411

Unit

Perihelion distance

Value

0.975002

1-sigma variation

Unit

Aphelion distance

Value

2.108031

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.027487

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.900460

1-sigma variation

Unit

MOID

Value

0.021685

1-sigma variation

Unit

Orbit Period

Value

699.0703

1-sigma variation

Unit

U parameter

Value

8.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	2.50573E-6	1.03485E-6	2.21104E-5	1.71552E-6	-1.13134E-5	-1.84272E-3
e	1.03485E-6	4.27538E-7	9.13675E-6	7.08787E-7	-4.59390E-6	-7.61068E-4
i	2.21104E-5	9.13675E-6	1.95311E-4	1.51482E-5	-9.70140E-5	-1.62612E-2
Ω	1.71552E-6	7.08787E-7	1.51482E-5	1.17516E-6	-7.59241E-6	-1.26166E-3
ω	-1.13134E-5	-4.59390E-6	-9.70140E-5	-7.59241E-6	9.30262E-5	8.30320E-3
M	-1.84272E-3	-7.61068E-4	-1.62612E-2	-1.26166E-3	8.30320E-3	1.35515E0

Date of computation: 2025-09-10 00:30 UTC

Note: The ASCII file is in a format suitable for Orbfit input.

Download ASCII file:

Physical properties

Rotation Period
Quality
Amplitude
Rotation Direction
Spinvector L
Spinvector B

Rotational properties

Value

Unit

Source

Rotation Period

Value

Unit

Source

[-]

Quality

Value

Unit

Source

[-]

Amplitude

Value

Unit

mag

Source

[-]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

Unit

Source

[-]

Spinvector B

Value

Unit

Source

[-]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Unit

Source

[-]

Taxonomy (all)

Value

Unit

Source

[-]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

26.795

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[2]

Diameter

Value

12 - 26*

Unit

Source

[2]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

Unit

mag

Source

[-]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Unit

Source

[-]

Download this part as:

Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	Estimation	Estimated from absolute magnitude

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

Unit

Source

[1]

Unobserved

Value

1470

Unit

Source

[1]

Normalized RMS of residuals

Value

0.590685

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-10-09.369221

Unit

Source

[2]

Last Observation

Value

2021-10-10.843719

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

25 (0)

Unit

Source

[1]

Radar Summary

First Observation
Last Observation
Delay (Discarded)
Doppler (Discarded)
Total Optical Observations (Discarded)

Radar

Value

Unit

Source

First Observation

Value

Unit

Source

[-]

Last Observation

Value

Unit

Source

[-]

Delay (Discarded)

Value

0 (0)

Unit

Source

[-]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[-]

Total Radar Observations (Discarded)

Value

0 (0)

Unit

Source

[-]

Note: The ASCII file is in a format suitable for Orbfit input.

Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	MPC	Minor Planet Center: https://www.minorplanetcenter.net

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

* - these fields are required

Close Approaches for 2021TN9 from 1950 to 2125

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1950-10-23 10:18	> 1 w	0.0528597	0.0137776	0.1281976
EARTH	1973-11-18 14:53	> 1 mo	0.1385955	0.0689539	0.1757794
EARTH	1998-09-29 11:53	> 1 w	0.1569022	0.0037716	0.2155905
EARTH	2021-10-12 22:55	< 1 min	0.0266664	0.0265447	0.0000406
EARTH	2065-11-07 00:23	> 1 mo	0.1069300	0.0256252	0.2317037
EARTH	2088-10-16 15:28	> 1 w	0.0255915	0.0222821	0.0847837
EARTH	2111-11-01 01:05	> 1 mo	0.0827643	0.0002049	1.8748003

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
338.39557602	280.26011362	0.02203120	MINIMUM
181.23499139	130.81337587	1.10817054	SADDLE
359.25861366	129.98274644	1.98282053	SADDLE
178.43313982	308.91615126	3.09373827	MAXIMUM

Download:

MOID Plots

Click on the images to zoom-in and zoom-out